1. Field of the Invention
The present invention relates to a photonic channelized receiver that employs Dense Wavelength Division Multiplexing (DWDM) technology and, more particularly, to a photonic channelized receiver useful for RF spectrum analysis.
2. Description of the Related Art
Electronic spectrum analyzers and channelized receivers for microwave and RF spectrum characterization applications are similar in operation in that they separate a wideband signal into a number of narrower individual channels. The electronic spectrum analyzer operates by scanning a narrow bandpass filter over the wideband frequency range, thus performing a serial scan of the band. In contrast, the channelized receiver performs the operation in parallel and includes of a plurality of bandpass filters connected in parallel to route the frequency bands of interest to separate detectors.
The principle shortcoming of RF spectrum analyzers is that they do not provide a near real time wideband spectral monitoring ability. In an RF spectrum analyzer, a narrowband filter is swept over the frequency range of interest so that only one band of frequencies is measured at a time. This approach precludes the ability to detect burst signals that exist for times shorter than the period of time required to sweep the band. Channelized receivers do provide the capability for wide bandwidth, near instantaneous signal detection. However, they are complex, have limited reliability and sensitivity, and are impractical if a large number of channels is required.
Electro-optical approaches for microwave and RF spectrum characterizations operate by the use of acousto-optic modulators, Bragg cells, or an etalon to convert a wideband electrical input signal into a proportional optical pattern that is detected and decoded to provide spectral information. However, electro-optical devices suffer from the inability to be implemented entirely in standard, commercial off-the-shelf (COTS) optical fiber components. Accordingly there remains a need for a practical and reliable device for RF spectrum analysis capable of near real time wideband spectral monitoring.